A. ROLE OF CORE The role of the Genetic Analysis and Sample Handling Core is: 1) To extract DNA from buffy coat and cheek cell samples from the nested case-control studies, measure and adjust DNA concentrations, and track and plate these specimens prior to genotyping. 2) To provide fast, efficient, and accurate genotyping to Project investigators at the lowest possible cost. 3) To identify, aliquot, and distribute for laboratory analysis plasma samples for biomarker analyses.